From 3139d3fb4d8dd40f7fe4114102a79edc2901e33f Mon Sep 17 00:00:00 2001
From: yh_cc <poemsmileyh@gmail.com>
Date: Thu, 5 May 2022 20:21:20 +0800
Subject: [PATCH] add instance to mapping

---
 .../{utils.py => packer_unpacker.py}          | 76 +++++++++++++++----
 fastNLP/core/dataset/instance.py              |  9 ++-
 2 files changed, 70 insertions(+), 15 deletions(-)
 rename fastNLP/core/collators/{utils.py => packer_unpacker.py} (58%)

diff --git a/fastNLP/core/collators/utils.py b/fastNLP/core/collators/packer_unpacker.py
similarity index 58%
rename from fastNLP/core/collators/utils.py
rename to fastNLP/core/collators/packer_unpacker.py
index 1a82aa23..f71b4113 100644
--- a/fastNLP/core/collators/utils.py
+++ b/fastNLP/core/collators/packer_unpacker.py
@@ -3,21 +3,69 @@ from functools import reduce
 from typing import Sequence, Mapping, Dict
 
 
-def unpack_batch_mapping(batch:Sequence[Mapping], ignore_fields:set)->Dict:
-    """
-    将 Sequence[Mapping] 转为 Dict 。例如 [{'a': [1, 2], 'b': 1}, {'a': [3], 'b': 2}] -> {'a': [[1, 2], [3]], 'b': [1, 2]}
+class MappingPackerUnPacker:
+    @staticmethod
+    def unpack_batch(batch:Sequence[Mapping], ignore_fields:set, input_fields:Dict)->Dict:
+        """
+        将 Sequence[Mapping] 转为 Dict 。例如 [{'a': [1, 2], 'b': 1}, {'a': [3], 'b': 2}] -> {'a': [[1, 2], [3]], 'b': [1, 2]}
+
+        :param batch:
+        :param ignore_fields:
+        :param input_fields:
+        :return:
+        """
+        dict_batch = defaultdict(list)
+        for sample in batch:
+            for key, value in sample.items():
+                if key in ignore_fields:
+                    continue
+                dict_batch[key].append(value)
+        return dict_batch
+
+    @staticmethod
+    def pack_batch(batch):
+        return batch
+
+
+class NestedMappingPackerUnpacker:
+    @staticmethod
+    def unpack_batch(batch:Sequence[Mapping], ignore_fields:set, input_fields:Dict):
+        """
+        将 nested 的 dict 中的内容展开到一个 flat dict 中
+
+        :param batch:
+        :param ignore_fields: 需要忽略的 field 。
+        :param input_fields: 不需要继续往下衍射的
+        :return:
+        """
+        dict_batch = defaultdict(list)
+        for sample in batch:
+            for key, value in sample.items():
+                if key in ignore_fields:
+                    continue
+                if isinstance(value, Mapping) and key not in input_fields:
+                    _dict_batch = _unpack_batch_nested_mapping(value, ignore_fields, input_fields, _parent=(key,))
+                    for key, value in _dict_batch.items():
+                        dict_batch[key].append(value)
+                else:
+                    dict_batch[key].append(value)
+        return dict_batch
 
-    :param batch:
-    :param ignore_fields:
-    :return:
-    """
-    dict_batch = defaultdict(list)
-    for sample in batch:
-        for key, value in sample.items():
-            if key in ignore_fields:
-                continue
-            dict_batch[key].append(value)
-    return dict_batch
+    @staticmethod
+    def pack_batch(batch):
+        dicts = []
+
+        for key, value in batch.items():
+            if not isinstance(key, tuple):
+                key = [key]
+            d = {key[-1]: value}
+            for k in key[:-1:][::-1]:
+                d = {k: d}
+            dicts.append(d)
+        return reduce(_merge_dict, dicts)
+
+
+class 
 
 
 def unpack_batch_nested_mapping(batch:Sequence[Mapping], ignore_fields:set, stop_deep_fields:set)->Dict:
diff --git a/fastNLP/core/dataset/instance.py b/fastNLP/core/dataset/instance.py
index db3d4be7..74ed3c9f 100644
--- a/fastNLP/core/dataset/instance.py
+++ b/fastNLP/core/dataset/instance.py
@@ -8,10 +8,11 @@ __all__ = [
     "Instance"
 ]
 
+from typing import Mapping
 from fastNLP.core.utils.utils import pretty_table_printer
 
 
-class Instance:
+class Instance(Mapping):
     r"""
     Instance是fastNLP中对应一个sample的类。每个sample在fastNLP中是一个Instance对象。
     Instance一般与 :class:`~fastNLP.DataSet` 一起使用, Instance的初始化如下面的Example所示::
@@ -69,3 +70,9 @@ class Instance:
 
     def __repr__(self):
         return str(pretty_table_printer(self))
+
+    def __len__(self):
+        return len(self.fields)
+
+    def __iter__(self):
+        return iter(self.fields)